This invention pertains to a top brush interrupt system for a car wash and more particularly to a top brush interrupt system which is able to distinguish pickup trucks from cars to prevent the top brush from entering the beds of the pickup trucks and causing damage or from dislodging or disturbing the contents of the beds of the pickup trucks.
In the past with car wash systems, as shown for example, in Nelson U.S. Pat. No. 4,685,169, difficulty has been encountered in distinguishing between cars and pickup trucks. Some prior car wash systems include a track gantry or frame that moves along the track and over the vehicle. Water outlets and brushes on the track gantry wash the car. One of the brushes is a top brush which is carried by a pair of arms pivoted on the frame and moved by air cylinder means for movement toward and away from the top of the vehicle. The top brush is rotated by a motor carried on one of said pair of arms for assisting vehicle washing.
In such past systems, the top brush was arranged to track the top of the vehicle. While the car wash worked satisfactorily for cars, problems were encountered with pickup trucks. The top brush would drop into the bed of the pickup truck and possibly pick up debris that would damage the pickup truck or the top brush. Additionally, debris from the pickup truck would sometimes cling to the top brush and damage the next vehicle to be washed.
To overcome these problems, a top brush interrupt system employing a mechanical limit switch was developed. The mechanical limit switch had an actuating arm that rested on a cross brace channel secured between the two arms supporting the top brush. The mechanical switch functioned to determine when the top brush dropped below the cab height on a pickup. The mechanical limit switch was on when the shaft of the top brush was more than a predetermined distance off the floor, e.g., 84 inches in one embodiment. The circuitry affected by the mechanical limit switch was activated during a period of time related to the car wash rearward travel time. The time period started several seconds after the top brush started to lower onto the hood of the vehicle allowing the top brush to drop onto the hood before activating the circuitry referred to above. This time period lasted until the track gantry stopped its reverse movement. Depending upon the model of car wash, this occurred at the time or several seconds after the rear of the vehicle was reached. If the mechanical limit switch made a transition from "on" to "off" (high to low) during said time period, the top brush would be raised and the top brush motor would be shut off.
The orginal top brush interrupt system was found to be unsatisfactory for the smaller pickup trucks being built currently. Merely lowering the the switch height would cause the top brush interrupt system to react to trunks of taller cars as if they were beds of trucks, with the results that such trunks would not be cleaned by the top brush. A second problem was that a number of short bed trucks were ignored by some models of car washes, as the car wash reached the rear of the truck prior to the top brush dropping into the bed. A third problem was that the mechanical limit switch was not accurate enough, since there was some pre-travel built into the switch. Further, the mechanical limit switches could not be set accurately.
An object of the present invention is to provide a car wash for vehicles, particularly pickup trucks, with an improved top brush interrupt system, wherein the disadvantages and difficulties with prior top brush interrupt systems are obviated.
Another object of the present invention is to provide an improved vehicle wash system which automatically determines whether the vehicle is a car or a pickup truck, wherein such determination involves a measurement of overall vehicle height, overall distance from the vehicle front to the drop off of the top brush and the overall distance from the drop off of the top brush to the rear of the vehicle.
Another object of this invention is to provide a car wash with a top brush interrupt system that incorporates an inductive proximity switch for detecting the position of the top brush relative to the vehicle, particularly, a pickup truck to more accurately and timely lift the top brush from the bed of the pickup truck and/or stop rotation of the top brush.
Yet another object of the present invention is to provide a car wash for a pickup truck with a top brush interrupt system that includes an inductive proximity switch and timing means for more accurately controlling termination of rotation of the top brush and prevention of the top brush from entering the bed of a pickup truck.
Other objects and advantages of the present invention will be made more apparent hereinafter.